MongoDB¶

The mongodb probe monitors a MongoDB server or replica set via serverStatus and per-database dbStats, covering connections, operation throughput, memory usage, replication state and database storage.

Quick start¶

# probes.d/20-mongodb.yaml — each file under probes.d/ is a YAML array of probes
- name: mongodb
  type: mongodb
  params:
    uri: mongodb://localhost:27017

Parameters¶

Parameter	Must set	Default	Description
`uri`	In practice	`mongodb://localhost:27017`	Connection URI; credentials go in it (mongodb://user:pass@host:27017/admin?authSource=admin). A secret: reference it with `${secret:…}`, `${env:…}` or `${file:…}` rather than writing it in the file. Example: `mongodb://monitor:secret@db01:27017/admin?authSource=admin`
`direct_connection`	No	`true`	Connect to the named host only; false for Atlas or replica-set aware routing
`timeout`	No	`10`	Connection and command timeout in seconds
`interval`	No	`60`	Seconds between collections
`instance_name`	No	-	Stable identity override for this server

Metrics¶

Metric	Unit	Description
`senhub.mongodb.up`	1	1 when the agent reached the MongoDB server this cycle
`mongodb.uptime`	s	Server uptime in seconds
`mongodb.connections.current`	{connection}	Current client connections
`mongodb.connections.available`	{connection}	Available connection slots
`mongodb.operations.count`	{operation}	Operations by type (insert/query/update/delete/getmore/command), tagged with `operation`
`mongodb.memory.usage`	By	Memory in use, tagged with `type` (resident, virtual)
`mongodb.index.count`	{access}	Index accesses by database, tagged with `database`
`mongodb.storage.size`	By	Storage allocated per database
`mongodb.document.operation.count`	{document}	Document count per database

Operational notes¶

For authenticated clusters embed credentials in the URI: mongodb://monitor:pass@host:27017/admin?authSource=admin.
Replica set members: set direct_connection: false and provide the replica set URI (mongodb://host1,host2,host3/?replicaSet=rs0) for topology-aware routing.
For MongoDB Atlas, use the Atlas connection string and set direct_connection: false.

Metric reference¶

Every metric this probe can emit. Metric is the OpenTelemetry name the OTLP, Prometheus and Zabbix outputs derive theirs from. Name is what a Nagios check and the API metrics= filter match. PRTG channel is the label PRTG shows, placeholders filled from the series' tags.

Metric	Name	PRTG channel	Unit	Description
`senhub.mongodb.up`	`senhub.mongodb.up`	MongoDB Up	#	1 if the agent reached the MongoDB server this cycle, 0 otherwise
`mongodb.uptime`	`mongodb.uptime`	Uptime	s	Seconds since the mongod process started (uptimeMillis / 1000)
`mongodb.connections`	`mongodb.connections.active`	Connections Active	#	Number of active (in-use) client connections (connections.active)
`mongodb.connections`	`mongodb.connections.available`	Connections Available	#	Number of connections available for new clients (connections.available)
`mongodb.connections`	`mongodb.connections.current`	Connections Current	#	Total number of current open connections (connections.current)
`mongodb.network.io`	`mongodb.network.bytes.in`	Network Bytes In	Bytes	Total bytes received over the network (network.bytesIn)
`mongodb.network.io`	`mongodb.network.bytes.out`	Network Bytes Out	Bytes	Total bytes sent over the network (network.bytesOut)
`mongodb.network.request.count`	`mongodb.network.requests`	Network Requests	#	Total distinct client requests received (network.numRequests)
`mongodb.operation.count`	`mongodb.operations.count`	Operations	#	Total operations executed by type (opcounters.*) — insert/query/update/delete/getmore/command
`mongodb.memory.usage`	`mongodb.memory.usage`	Memory	Bytes	Memory usage in bytes (mem.resident / mem.virtual — converted from MB)
`mongodb.document.operation.count`	`mongodb.document.operations`	Documents	#	Document operations since startup (metrics.document.*) — deleted/inserted/returned/updated
`mongodb.cache.operations`	`mongodb.cache.operations`	Cache	#	WiredTiger cache page operations — read: pages read into cache; write: pages written from cache
`senhub.mongodb.lock.queue.length`	`mongodb.active.reads`	Active Reads Queued	#	Clients queued waiting for a read lock (globalLock.currentQueue.readers)
`senhub.mongodb.lock.queue.length`	`mongodb.active.writes`	Active Writes Queued	#	Clients queued waiting for a write lock (globalLock.currentQueue.writers)
`mongodb.collection.count`	`mongodb.collection.count`	Collections	#	Number of collections in the database (dbStats.collections)
`mongodb.data.size`	`mongodb.data.size`	Data Size	Bytes	Uncompressed in-memory size of all documents (dbStats.dataSize)
`mongodb.index.count`	`mongodb.index.count`	Indexes	#	Number of indexes across all collections (dbStats.indexes)
`mongodb.index.size`	`mongodb.index.size`	Index Size	Bytes	Total size of all indexes on disk (dbStats.indexSize)
`mongodb.storage.size`	`mongodb.storage.size`	Storage Size	Bytes	Total amount of disk space allocated to all collections (dbStats.storageSize)